doctorwho wrote:Okay, here goes, and I apologize in advance if this gets too technical ...
Methylene chloride (a.k.a. dichloromethane) and triclosan (a.k.a. 5-chloro-(2,4-dichlorophenoxy)phenol, among other names) both contain chlorine. One of the general rules of chemistry is "like dissolves like", so methylene chloride probably is a good solvent for triclosan (and vice-versa, of course). The other thing about triclosan is that it is also a phenol, a class of compounds that are weak organic acids. In the case of triclosan, the presence and positions of the chlorines in the molecule are such that they enhance the acidity; in technical terms, phenols typically have pKa's around 9 to 10 [pKa is a log scale that measures acid strength with low numbers indicating stronger acids], but triclosan's pKa is around 7.6, about 100-fold stronger. The acid nature of triclosan may contribute to its negative effects on finishes.
The other comment I alluded to concerning methylene chloride is that it is an alkyl halide, a fact that has missed the attention of synthetic organic chemists at times ... there have been instances when a chemist has tried to use it as a solvent (or cosolvent) in a reaction which includes a reagent that reacts with alkyl halides, so the desired reaction goes haywire (yes, that is a scientific term ...!).
Hey, what's that zzzzzzzz sound I hear?!?!
Pshaw - I went to Med School, so I am one of those Exclusively Organic dudes, Gary. Physical and/or industrial chemistry is a distraction at best to us. BUT, give me a good pH-neutral or mildly-acidic small-molecule solute with a DMSO transport carrier and I will happily expound on tissue transfer rates and infusion protocols, and resulting local vs. systemic serum concentration profiles. And follow up with an apertif of metaboloids and by-products of a good trip through the body's phenomenal superstar of an organic chemistry factory (and principal endocrine gland), the liver.
But we don't do free chlorides, ours must be safely bound and looking across a steep and deep valence trough to prevent instabilty and ready conversion to potentially toxic metaboloids. Gimme a lab and I can whip up, with little effort, some nice antibacterial alkylated phenols. Really get you off big-time, y'know. And, 2,4,4'-trichloro-2'-hydroxydiphenyl ether has been shown to be of therapeutic effectiveness in the treatment of acne vulgaris (Darn Gross Big Zits) (That's also triclosan, to you non-chemists, BTW!) It's a great parent phenol, very versatile.
Plus, toss in some novel lipophilic glyceride esters of halogenophenols that are crafted to be stable towards hydrolysis by esterases and at the same time labile towards hydrolysis by lipases and you have something that is well-indicated in the prophylaxis of acne vulgaris. Yippee! Zit Cream in an appropriate water-soluble base. That's because you progressively reap lipase catalysed release of the halogenophenol inside the subject pilosebaceous follicle. Gotta get that treatment into that skin follicle and make it stay there long enough to do some good, though, but that's the job of the lipase in part.
Damn, maybe I should have been a simple dermatologist instead of a research physician specializing in remote-sensing and non-invasive diagnostics......
